PATTERNS OF CHORIOCAPILLARIS FLOW SIGNAL VOIDS IN CENTRAL SEROUS CHORIORETINOPATHY An Optical Coherence Tomography Angiography Study

Purpose: To investigate choriocapillaris flow signal void distribution on optical coherence tomography (OCT) angiography in central serous chorioretinopathy (CSCR) and its correlation to choroidal vessel morphology. Methods: Fifty-three CSCR eyes (48 patients) and 34 healthy control eyes were included, retrospectively. Exclusion criteria were refractive error >2D, previous laser or photodynamic therapy, low-quality OCT angiography, or excessive shadowing artifacts. Choriocapillaris OCT angiography scans were processed by local-threshold binarization to identify signal voids, and extract their cumulative area. The locations of the two largest voids in each eye were reported on the corresponding enhanced depth imaging OCT raster scan. Choriocapillaris thickness and diameter of underlying outer choroidal vessels were measured at the level of flow voids and of adjacent outer choroidal vessels, not colocalizing with voids. Results: There were 22 acute, 16 recurrent, and 15 chronic CSCR eyes. Total flow void area was larger in CSCR than control eyes. In univariate analysis, the total flow void area on OCT angiography increased with age (P = 0.0002), duration since CSCR diagnosis (P = 0.004), extension of autofluorescence alterations (P = 0.016), and CSCR severity (P < 0.0001). In multivariate analysis, age (P = 0.014) and CSCR type (P = 0.046) influenced independently the total flow void area. On enhanced depth imaging OCT, outer choroidal vessel diameter was higher (P < 0.0001), and choriocapillaris was thinner (P< 0.0001) at flow voids compared with adjacent sites, independently from eccentricity from the fovea. Conclusion: Choriocapillaris flow voids colocalize with choriocapillaris thinning and deep choroidal vessel dilation in CSCR eyes. Age and CSCR severity influence choriocapillaris flow, a key contributor to CSCR pathophysiology and clinical expression.